Evolution of charm-meson ratios in an expanding hadron gas

TL;DR

This paper investigates how charm-meson ratios evolve over time in an expanding hadron gas post-heavy-ion collision, highlighting the impact of reaction rates with t-channel singularities on meson production ratios.

Contribution

It introduces a detailed analysis of charm-meson ratio evolution considering reaction rate singularities, providing new insights into charm meson dynamics after kinetic freeze-out.

Findings

Charm-meson ratios can significantly differ from predictions based on $D^ ext{*}$ branching fractions.

Reaction rates with t-channel singularities influence the time evolution of charm mesons.

The study offers a refined understanding of charm-meson production in hadron gases.

Abstract

We study the time evolution of the numbers of charm mesons after the kinetic freeze-out of the hadron gas produced by a central heavy-ion collision. The $\pi D^\ast \to \pi D^\ast$ reaction rates have $t$-channel singularities that give contributions inversely proportional to the thermal width of the $D$. The ratio of the $D^0$ and $D^+$ production rates can differ significantly from those predicted using the measured $D^\ast$ branching fractions.